When casting molten material in copper moulds to form anodes for electrorefining, anode material is usually poured into an open top mould cavity and the mould is cooled with water from the bottom by an external spray system, or by an internal system of water channels. The repeated pouring of hot molten metal on the top side of the mould and cooling on the bottom side or internally in the mould results in gradual mould warpage. The corners of the generally rectangular mould are gradually lifted up and the mould as well as the castings get a concave shape. Cracks also develop and the mould has to be discarded. The average life of a mould as now employed at INCO LIMITED for casting copper anodes is about 550 to 750 tonnes of metal cast. The mould as now used must then be discarded either because of the damage to the mould cavity or because of extensive mould warpage (-12 to -14 mm).